Rationalize URLs with Realtion_Value so that RelationId numeric is always in the same position.
This behaviour is required when custom controller needs to pre-process that id e.g. for security
See sample controller below: it would be called like   /c/myeditor/6757
and 6757 needs to always remain there!
so then crud urls shall look like
/c/myeditor/6757/upload_file
/c/myeditor/6757/delete_file/75
...

 function myeditor($id) {
   if ( $this->can_edit_this_id( $id ) ) {
      // do all the nice crud stuff